Tin Derivatives Research Articles

Compounds of potassium and tin(II) with diiminopyridine ligands: EPR spectroscopy and theoretical study

Potassium and tin(II) derivatives of the paramagnetic forms of the redox-active 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine were synthesized and studied by means of EPR spectroscopy. It was shown that the reaction with metallic potassium involves the three-electron step reduction of the organic ligand to form a radical anion, dianion, and trianion radical, respectively. The reactions of the tin(II) diiminopyridine derivatives with metallic magnesium give complexes comprising the radical anion form of the ligand and a low-valence metal center. The geometries of the paramagnetic products and their spin density distributions were explored in terms of the density functional theory.

Deposition of SnS Thin Films from Sn(II) Thioamidate Precursors

Two thioamide pro-ligands, R1N(H)C(=S)R2 (R1 = t-Bu, R2 = i-Pr and R1 = i-Pr, R2 = i-Pr), were synthesized by treatment of the corresponding amides with Lawesson’s reagent. Reactions of [Sn{N(SiMe3)2}2] with two molar equivalents of each thioamide pro-ligand yielded the tin(II) thioamidate species, bis(2-methyl-N-(1-methylethyl)-propanethioamide)tin(II) and bis[N-(1,1-dimethylethyl)-2-methyl-propanethioamide]tin(II). Both of the new tin compounds have been characterised by 1H, 1C and 119Sn NMR spectroscopy and elemental analysis. In addition, the solid-state structure of bis(2-methyl-N-(1-methylethyl)-propanethioamide)tin(II) has been determined through a single crystal X-ray diffraction analysis and shown to display a monomeric constitution in which the tin(II) centre occupies a distorted pseudo-square pyramidal geometry defined by the N2S2 donors and the stereochemically active lone pair. Both tin(II) derivatives have been assessed for their potential as single source precursors to SnS by TGA and by NMR...

Sn- and Ge- triorganometallics exert different cytotoxicity and modulation of migration in triple-negative breast cancer cell line MDA-MB-231

Among a variety of metal containing organic compounds, tin derivatives are enjoying an increasing interest and appear to be very promising as potential drug candidates. We studied eight organometallic derivatives, nuclear retinoid X receptor (RXR) ligands and two germanium containing derivates that do not serve as RXR ligands. Tributylgermanium chloride (TBGe) and triphenylgermanium chloride (TPGe) did not inhibit growth of human triple negative MDA-MB-231 breast cancer cells. On the other hand, the tributyltin derivatives were highly, the triphenyltin derivatives less cytotoxic, both groups with IC50 values of nanomolar range. All trialkyltin derivatives (tributyltin chloride, tributyltin bromide, tributyltin iodide, tributyltin hydride) and three triaryltin derivatives (triphenyltin chloride, triphenyltin hydride and triphenyltin hydroxide) caused caspase-3/7 dependent apoptosis. Those derivatives that showed no or weak cytotoxicity, TBGe, TPGe, and triphenyltin acetate, we found to reduce migration of tested triple negative breast cancer cells.

Synthesis of Mono-, Bis- and Tris(pentafluoroethyl)tin Derivatives, (C2 F5 )4-n SnXn (X=Ph, Me, Cl, Br, Cp; n=1-3).

For (pentafluoroethyl)phenylstannanes, (C2 F5 )4-n SnPhn (n=1-3), and dimethylbis(pentafluoroethyl)stannane, (C2 F5 )2 SnMe2 , a high yield synthesis was developed by the use of LiC2 F5 as a C2 F5 transfer reagent. The treatment of these products with gaseous hydrogen chloride or hydrogen bromide afforded (C2 F5 )4-n SnXn (X=Cl, Br; n=1-3) in good yields. The (pentafluoroethyl)stannanes were fully characterized by 1 H, 13 C, 19 F and 119 Sn NMR, IR spectroscopy and mass spectrometry. The treatment of the (pentafluoroethyl)tin halides (C2 F5 )4-n SnXn with 1,10-phenanthroline (phen) led to the formation of the corresponding octahedrally coordinated complexes [(C2 F5 )4-n SnXn (phen)], the structures of which were elucidated by X-ray diffraction analyses. The bromostannane (C2 F5 )3 SnBr reacted with sodium cyclopentadienide to give the (η1 -cyclopentadienyl)tris(pentafluoroethyl)stannane, (C2 F5 )3 SnCp, for which single-crystal X-ray diffraction analysis could be performed. The coupling constants 1 J(119 Sn,13 C) and 2 J(119 Sn,19 F) of all new stannanes are strongly correlated and sensitive to the substitution pattern at the tin atom. For both coupling constants a negative sign could be assigned.

A stannatrane-like [4.4.4.01,6] heterotricyclic stannate anion possessing rhodanide antennae: A chromoreactand for Fe3+, Cu2+ and Co2+ ions

Exploration of an aminotrisphenol ligand (H3L) to synthesise heterocyclic tin derivatives led to the unexpected formation of a stannatrane-like [4.4.4.01,6] heterotricyclic stannate anion [LSnCl2]− (1). Further, its metathesis reaction with ammonium thiocyanate provided access to its thiocyanate derivative [LSn(NCS)2]− (2), which proved to be a chromophoric probe. The characterization methods applied, such as elemental analysis, various spectroscopic methods (FT-IR, NMR (1H, 13C, 119Sn), UV–Vis, Mass) and X-ray crystallography (for 2) are in accord with the formation of these ionic compounds. The rhodanide functionalized stannatrane-like compound (2) was isolated as triethylammonium salt with distorted octahedral environment around Sn generated by the tripodal O3N donor system and the N atoms of two cis configured thiocyanates. This particular organization of rhodanides imparted chelator and chromophoric character to 2 and enhanced its colorimetric and optical response towards some metal ions (such as Fe3+, Cu2+ and Co2+ ions) as compared to the free tripodal ligand (H3L) and ammonium thiocyanate. The role of 2 as a bidentate ligand for the chelation of metal ions may be responsible for the enhanced stability of metal complexes as well as the observed spectral behaviour.

N,C,N-chelated antimony(III), bismuth(III) and tin(IV) derivatives of 1,1′-ferrocenedicarboxylic acid

N,C,N-intramolecularly coordinated antimony(III) and bismuth(III) oxides (ArMO)2 [where Ar=[2,6-(Me2NCH2)2C6H3]−, M=Sb (1) or Bi (2)] reacted with 1,1′-ferrocenedicarboxylic acid fc(COOH)2 (fc=ferrocene-1,1′-diyl) under formation of corresponding carboxylates fc(COO)2SbAr (4) and [fc(COO)2BiAr]2 (5). Similarly, the treatment of fc(COOH)2 with tin(IV) carbonate ArSnPhCO3 (3) led to the carboxylate fc(COO)2Sn(Ph)Ar (6). All compounds were characterized by the help of multinuclear NMR, Raman, IR and UV–Vis spectroscopy and in the case of 4 and 5 using single-crystal X-ray diffraction analysis.

Multiple Reactivity of SnII Complexes Bearing Catecholate and o‐Amidophenolate Ligands

The reactivity of tin(II) catecholate complex CatSn (1) (where Cat = 3,6‐di‐tert‐butylcatecholate dianion) and two o‐amidophenolate complexes DippAPSn (2) and PhAPSn (3) [where DippAP = 4,6‐di‐tert‐butyl‐N‐(2,6‐diisopropylphenyl)amidophenolate; PhAP = 4,6‐di‐tert‐butyl‐N‐(phenyl)amidophenolate dianions] towards different reagents is reported. Products of the insertion of 1 and 2 into the S–S bond of tetramethylthiuram disulfide were obtained and characterised by X‐ray diffraction analyses. The low temperature oxidation of complexes 1 and 2 with 2‐ethoxy‐3,6‐di‐tert‐butylphenoxy radical enabled us to detect formation of paramagnetic tin(II) derivatives containing the radical‐anion form of the redox‐active ligand. The reaction of tin derivative 3 with Ni(CO)4 leads to substitution of one of the CO groups in the latter with the formation of a new bimetallic product.

Tin-catalyzed hydrophosphination of alkenes.

Simple tin derivatives, Cp*2SnCl2 (1) and Ph2SnCl2 (2), catalyze the hydrophosphination of alkene substrates with diphenylphosphine. Competitive dehydrocoupling to give Ph4P2 was observed, but this side reaction can be mitigated when the catalysis is conducted under an H2 atmosphere. Efforts to prepare stable tin bis(phosphido) compounds commonly resulted in decomposition to Ph4P2. Lewis acidic inorganic tin compounds do not show dehydrocoupling reactivity. It was found that the Lewis acid, B(C6F5)3, is able to engage in the hydrophosphination of alkenes, but it is poorly effective under the conditions tested.

Redox-induced C–C bond formation reaction between mono-o-amidophenolate tin complexes and allylhalides

The reaction of tin(II) and tin(IV) mono-o-amidophenolate complexes based on redox-active 4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-aminophenol (dippAPH2) with allylhalides is reported. This process includes oxidative addition of all-Hal (where all = allyl, Hal = Cl, Br, I) molecule to the non-transition metal complex and results in the alkyl transfer to carbon ring with the formation of new CC coupled product. The interaction proceeds at room temperature and gives new tin(IV) derivatives containing iminocyclohexa-1,4-dienolate ligand. The “oxidative addition” type products have been characterized by X-ray crystallography.

Synthesis and characterization of tributyltin derivatives from 4‐oxo‐4‐(arylamino)butanoic acids and their in vitrobiological activity against cervical cancer cell lines

Uterine (cervix and corpus) cancer is one of the major causes of mortality in women in Mexico. Organotin carboxylated derivatives have shown high cytotoxic activity against various cell lines of human origin. We describe the synthesis of three new tri‐n‐butyltin derivatives from 4‐oxo‐4‐(arylamino)butanoic acids; their structures were confirmed using spectral data (1H NMR, 13C NMR, 119Sn NMR and infrared), elemental analyses, mass spectrometry and X‐ray diffraction. All the tri‐n‐butyltin carboxylates exhibit 1 J (119/117Sn–13C) coupling satellites in solution and lie in the range 357 to 339 Hz, suggesting a tetrahedral geometry around the tin atom. The polymeric structures of two of the derivatives and the monomeric structure of another were confirmed using X‐ray crystallography. Using succinic anhydride as raw material, five N‐substituted succinamic acid compounds were synthesized by the acylation reaction with aniline, 4‐nitroaniline, 4‐nitro‐3‐(trifluoromethyl)aniline, 2‐amino‐5‐nitrothiazole and 4‐aminoantipyrine. From these compounds, five tin derivatives were prepared and their in vitro anti‐proliferative effect on HeLa, CaSki and ViBo cell lines was screened. All of the compounds showed potency against all three strains and null or low cytotoxic activity (necrotic) as well. The most potent of our derivatives as an anti‐proliferative agent against the three cell lines was tributylstannyl 4‐oxo‐4‐[(3‐trifluoromethyl‐4‐nitrophen‐1‐yl)amino]butanoate, exhibiting an IC50 value of 0.43 μM against the HeLa cell line. Copyright © 2014 John Wiley & Sons, Ltd.

Synthesis and structural elucidation of bioactive triorganotin(IV) derivatives of sodium deoxycholate

Trimethyl (1), tributyl (2), and triphenyl tin (3) derivatives of sodium (R)-4-((3R,5R,8R,9S,10S,12S,13R,14S,17R)-3,12-dihydroxy-10,13-dimethyl-hexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)pentanoate (sodium deoxycholate) were synthesized by refluxing sodium deoxycholate with the corresponding triorganotin(IV) chloride in 1 : 1 M ratio. All the three compounds were characterized by elemental analysis, infrared spectroscopy, 1H, 13C, 119Sn NMR, and X-ray diffraction studies. From FT-IR spectra, Δν values proposed bridging or chelating behavior of the ligand. The three compounds gave a trigonal bipyramidal geometry in the solid state and tetrahedral geometry in solution. Single crystal of 1 showed polymeric trigonal bipyramidal geometry. Synthesized compounds obtained were screened for their antimicrobial and antitumor activities against A2780 cell line. Results revealed that only 2 showed significant antibacterial activity. However, all the three compounds exhibited promising antifungal and anticancer activities.

The in Vitro Effect of Tin Derivatives on Cell Lines of Canine Osteosarcoma (D-17), B-Cell Lymphoma (CL-1) and T-cell Leukaemia (GL-1)

The in Vitro Effect of Tin Derivatives on Cell Lines of Canine Osteosarcoma (D-17), B-Cell Lymphoma (CL-1) and T-cell Leukaemia (GL-1)

Extending the Family of N‐Heterocyclic Heavy Carbene Analogues: Synthesis and Crystal and Molecular Structures of MeN[CH2C(O)N(R)]2Sn (R = Me2NCH2CH2, PhCH2, Me3CCH2)

AbstractWe report herein the synthesis of the N‐methyl‐N′N″‐diorganoiminodiacetic acid diamides MeN[CH2C(O)N(R)H]2 [3: R = Me2N(CH2)2; 4: R = PhCH2; 5: R = Me3CCH2] and the novel tin(II) derivatives MeN[CH2C(O)N(R)]2Sn [6: R = Me2N(CH2)2; 7: R = PhCH2; 8: R = Me3CCH2]. The compounds were characterized by elemental analyses, 1H NMR spectroscopy (3–5), solid‐state 13C and 119Sn NMR spectroscopy (8), and single‐crystal X‐ray diffraction analysis (5, 8). Compound 8 shows intramolecular N→Sn and intermolecular O→Sn interactions with distances of 2.370(2) and 2.406(2) Å, respectively, the latter indicating that 8 is a coordination polymer. DFT calculations revealed covalent Sn–NC(O) and coordinative N→Sn and C=O→Sn bonds. The wB97Xd functional, which takes into account dispersive interactions, was employed for a correct theoretical description of, in particular, the latter bond.

Organic Amides as Suitable Precursors to Stabilize Stannylenes

This contribution demonstrates that deprotonated amides (amidates) can be used to stabilize stannylenes. Thus, the dimeric stannylene [Sn2{μ-tBuNC(O)tBu}2Cl2] (1) was obtained by treating Li{tBuNC(O)tBu} with 1 equiv of SnCl2. Chloride exchange reactions of 1 with Li{tBuNC(O)tBu} and Li(HMDS) (HMDS = N(SiMe3)2) lowered aggregation, affording the monomeric tetra- and tricoordinated tin(II) derivatives [Sn{tBuNC(O)tBu}2] (2) and [Sn{tBuNC(O)tBu}(HMDS)] (3), respectively. Alternatively, 3 can be prepared by direct deprotonation of the amide with Sn(HMDS)2. Compounds 1–3 are stannylenes that contain an unprecedented SnNCO four-membered ring.

New Conjugated Oligothiophenes Containing the Unique Arrangement of Internal Adjacent [All]‐S,S‐Oxygenated Thiophene Fragments

The quest for obtaining conjugated oligothiophene-containing molecules with narrower HOMO-LUMO gaps and higher oxidation and reduction potentials is the subject of this study. Molecules containing the bithiophene tetraoxide (2) and the terthiophene hexaoxide (3) moieties were prepared and studied. They were obtained by transferring oxygen atoms to the corresponding dibromo oligothiophenes with the HOF⋅CH3CN complex and then cross-coupling them with either thiophene- or acetylene tin derivatives. The photophysical and electrochemical studies of the products revealed that this particular class of mixed thiophenes is characterized by significantly smaller frontier orbital gaps and higher oxidation and reduction potentials compared with any other arrangement of oligothiophenes including various [all]-S,S-oxygenated thiophene derivatives.

Synthesis, structural characterization and in vitro cytotoxic activity of novel polymeric triorganotin(IV) complexes of urocanic acid

Two novel triorganotin carboxylate complexes of the biologically active urocanic acid have been synthesized and characterized. Elemental analysis, melting point, spectroscopic techniques – IR, 1H, 13C and 119Sn NMR – mass spectrometry and X‐ray diffraction studies have been used for structural characterization. Crystal structures of the tin(IV) derivatives show that urocanic acid acts as a bridging bidentate ligand through its imidazole nitrogen atom and its carboxylic group, producing a polymeric one‐dimensional chain. The molecular structures of the complexes, catena‐poly‐tri(n‐butyl)tin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (1) and catena‐poly‐triphenyltin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (2), present a distorted trigonal–bipyramidal configuration. This is further confirmed by 119Sn NMR in the solid state. The tin(IV) derivatives form double‐stranded ribbons via N―H…O―H bonds. Nevertheless, the compounds are essentially monomeric in solution, with a tetrahedral configuration as observed by 119Sn NMR in solution. The cytotoxic activity of the titled compounds has been tested against six human cell lines and the corresponding IC50 values are reported. Both tin(IV) compounds have a high to very high in vitro cytotoxic activity against the tumor cell lines K562, HCT‐15 and MCF‐7. Compound 1 is 86 times more active than cisplatin in the HTC‐15 cell line. Copyright © 2012 John Wiley & Sons, Ltd.

Synthesis and characterization of new tin derivatives derived from 3,5,6-trichlorosalicylic acid: Cage, chain and ladder X-ray crystal structures

Six new tin complexes of the formulae [(Ph3Sn)2(PhSn)10(Sn)2(μ2-O)8(μ3-O)18(C7HCl3O3)2] (1), {[(n-Bu)3Sn]2(C7HCl3O3)}n (2), [(Me3Sn)2(C7HCl3O3)]n (3), [(Ph2Sn)(C7HCl3O3)2] (4), [(n-Bu)2Sn(C7HCl3O3)2] (5) and [(Me2Sn)4(C7HCl3O3)2(μ3-O)2(CH3O)2] (6) have been obtained from 3,5,6-trichlorosalicylic acid and an organotin chloride or organotin oxide. All the complexes were characterized by elemental analysis, FT-IR and NMR (1H, 13C and 119Sn) spectroscopy; complexes 1, 3 and 6 were further characterized X-ray crystallography diffraction analyses. The structural analyses reveal that complex 1 has a novel cage structure, which contains two triphenyltin nuclei, 10 monophenyltin nuclei and two inorganic tin nuclei; complex 3 has an infinite chain structure and complex 6 displays a typical ladder structure.

Synthesis, characterization, biological studies and in vitro cytotoxicity on human cancer cell lines of titanium(IV) and tin(IV) derivatives with the α,α′‐dimercapto‐o‐xylene ligand

The reaction of α,α′‐dimercapto‐o‐xylene (H2dmox) with different precursors such as SnMe2Cl2, [Ti(η5‐C5H5)2Cl2] and [Ti(η5‐C5H4Me)2Cl2] (1:1) in the presence of two equivalents of NEt3 yielded the complexes [SnMe2(dmox)] (1), [Ti(η5‐C5H5)2(dmox)] (2) and [Ti(η5‐C5H4Me)2(dmox)] (3), respectively. 1–3 have been characterized by spectroscopic methods; in addition, complex 3 has been determined by X‐ray diffraction studies. Furthermore, structural studies based on density functional theory calculations of 1 and 2 have been carried out. The cytotoxic activity of 1–3 was tested against the tumour cell lines human adenocarcinoma HeLa, human myelogenous leukaemia K562 and human malignant melanoma Fem‐x. The results of this study show a higher cytotoxicity of the tin(IV) complex (1) in comparison to their titanium(IV) counterparts (2 and 3) as well as an improvement in the cytotoxic activity of compounds 2 and 3 compared to their titanocene(IV) dichloride analogues [Ti(η5‐C5H5)2Cl2] and [Ti(η5‐C5H4Me)2Cl2]. In view of the relatively high cytotoxicity of compound 1, a detailed study on the effects of the in vitro treatment of cancer cell lines using this compound was carried out. Thus cell cycle experiments on all the studied cell lines treated with 1 show that this complex seems to cause disturbances in the G1 phase of HeLa, and in the G1 and G2/M phases of Fem‐x cell line, while almost no disturbances were observed in the cycle of K562 cells treated with 1. Finally, DNA laddering method showed that treatment of the HeLa and Fem‐x cell lines with IC90 doses of 1 resulted in the induction of apoptosis. Copyright © 2012 John Wiley & Sons, Ltd.

Tin(II) and Tin(IV) Compounds with Scorpion‐Shaped Ligands – Intramolecular N→Sn vs. Intermolecular O→Sn Coordination

AbstractThe syntheses of new potentially tetradentate ligands of the type RN(CH2CMe2OH)2 (1, R = Me2NCH2CH2; 2, R = MeOCH2CH2), their tin(II) derivatives RN(CH2CMe2O)2Sn (3, R = Me2NCH2CH2; 4, R = MeOCH2CH2), the pentacarbonyltungsten complexes RN(CH2CMe2O)2SnW(CO)5 (5, R = Me2NCH2CH2; 6, R = MeOCH2CH2) and their oxidation products with bromine, RN(CH2CMe2O)2SnBr2 (7, R = Me2NCH2CH2; 8, R = MeOCH2CH2), are reported. The compounds were characterized by multinuclear NMR spectroscopy, elemental analysis, electrospray ionization mass spectrometry and single‐crystal X‐ray diffraction analysis. DFT calculations on compounds 3, 7 and 8 suggest the preference of dimeric over monomeric structures.

Synthesis of styrene-methyl methacrylate block copolymers using germanium and tin derivatives containing a macroradical

Block copolymerization of polystyrene synthesized in the presence of catecholate complexes of Group IV nontransition elements was studied. The effect of Ge(IV) and Sn(IV) o-semiquinolate derivatives formed in the course of styrene polymerization on the formation of the macroinitiator of methyl methacrylate polymerization was examined.